Featured Site of the Month

The Observatory at DeerRidge with LOYD OVERCASH

Featured Site of the Month:Home Observatories and Astrophotography  Page Two

Nebulae

Nebulae, Clusters and Comets

Nebulae  The Dumbbell and the Owl

The Dumbbell Nebula Nebula

Located in the constellation Vulpecula, at a distance of approximately 1,360 light years, is the planetary nebula M27, also known by its given name, the Dumbbell Nebula and its New General Catalog number, NGC 6853; it was also the first planetary nebula discovered by Charles Messier in 1764. At the center of this historic nebula is a white dwarf star, one who's size is estimated to be the largest such type so far discovered. One of the nicer aspects of M27 is that in comparison to other nebulae, it is relatively luminous, with a visual magnitude of 7.4 and easily seen through a pair of binoculars. Below: "M-27 taken from Ft. Davis on 7-16-09. Exposure was RGB = 30 min. each. Processed in MaxIm and Photoshop."  Loyd Overcash.

A planetary nebula is an emission nebula consisting of an expanding glowing shell of ionized gas and plasma ejected during the asymptotic giant branch (AGB) phase of certain types of stars late in their life. The name originated in the 18th century because of their similarity in appearance to giant planets when viewed through small optical telescopes, and is unrelated to the planets of the solar system. They are a relatively short-lived phenomenon, lasting a few tens of thousands of years, compared to a typical stellar lifetime of several billion years.  Planetary nebula at Wikipedia. In addition to being the second largest discovered (second in size only to NGC 7293, the Helix) nebulae like M27 are also referred to as bipolar, meaning that they are symmetric with respect to one axis which is thought to be the rotation axis of the original star. [5]

The Owl Nebula

Located within the well-known and historically rich constellation Ursa Major or "Great Bear" is the large Owl planetary nebula, also know as M97 or NGC 3587. At a little over 3' in diameter, the nebula generally appears in small telescopes as a grayish patch of light with a slightly brighter center; its form and namesake can easily be recognized by unfocusing or averting one's view slightly, bringing the "eyes" of the owl into focus which are the result of two slightly darker spots within the nebula. In addition to being host to one of the most recognizable patterns in our northern sky, the Big Dipper, Ursa Major is also the location of numerous other stellar objects that include 42 double stars, 11 galaxies and 41 variable stars. Throughout history, the constellation's Big Dipper has also been known under a variety of names such as Arktos by the Greeks, The Cart by the Bulgarians, King Arthur's chariot by the Welsh, Thor's chariot by the Germanic tribes and The Plough in English tradition. Says Loyd of his image below: "M-97, the Owl Nebula, is a Planetary Nebula located in Ursa Major. It lies about 1500 light years away. This image was taken on 1-30-06 from Ft. Davis, Tx. Exposure was L=60 min. and RGB=20 min.each." [6]
M97, the Owl Nebula in Ursa Major, is an interesting object for backyard viewing. It lies relatively nearby at 2,300 light-years from our Sun, so it appears 3.2 arcminutes in diameter - only ten times smaller than the Full Moon. The nebula's unusual name goes back to Lord Rosse, who found in 1848 a striking resemblance to the face of an owl, with two dark circular perforations and "a star in each cavity" giving the impression of two gleaming eyes. This description may sound a little over- imaginative, but if you take a look at his drawing you will see that it's accurate.  M97 - Planetary Nebula in Ursa Major courtesy the Night Sky Info website.

Clusters

The Pearls of the Universe

Loyd's Images of M5 & M37

M5Kirch's Globular Cluster

He was a German astronomer, son of a shoemaker who began his working career in the art of calendar making, eventually finding his way into astronomy via studies under the famous Polish astronomer Hevelius while in Danzig. His name was Gottfried Kirch and by 1700, he had attained an appointment by Frederick I of Prussia as the first astronomer of the Prussian Royal Society of Sciences. It was on May 5, 1702, while observing a comet, that Gottfried Kirch dicovered the globular cluster M5 and though Charles Messier later observed the object in 1764, he was unable to see any stars within this area of "nebulosity" (the brightest stars have an apparent magnitude of 12.2). It was William Herschel who, in 1791, was the first to resolve individual stars in the cluster, counting around 200 of the more than 100,000 in the cluster. [7].
Located in the constellation Serpens, "This image of M-5 was taken on 6-26-09 from Ft. Davis with the SBIG STL-6303 camera and a 14.5" RCOS. Exposure was RGB = 30 min. each and processed in Maxim and Photoshop.".  Loyd Overcash

Seen at far left is an image of Loyd and his telescope, a 16-inch RCOS (RC Optical Systems) Ritchey-Chretien with Ion Milled optics. At near left, "M-3 was also taken on 6-26-09. Same as above". M3, also known as NGC 5272, is a tad brighter than M5 above, with an apparent magnitude of 6.2 (M5's apparent magnitude is 6.65) and is located 33,900 light years from Earth, in the constellation Canes Venatici. It was discovered by Charles Messier in 1764 and finally resolved into stars by William Herschel around 1784. The constellation Canes Venatici, created by the astronomer Hevelius around 1687, comprises two stars that are supposed to represent the two hunting dogs Boötes held on a leash, named by Hevelius Asterion and Chara.

Giovanni Battista Hodierna & M37

While it was Charles Messier who rediscovered M37 in September of 1764, it was the lesser known Italian astronomer Giovan Battista Hodierna who originally recorded this open cluster in the constellation Auriga, sometime prior to 1654. M37, which is also known as NGC 2099, is the brightest and most compact of the three open clusters located in Auriga (the other two being M36 and M38) and is composed of over 500 stars. The open cluster is estimated to be between 3,600 and 4,700 light years distance from Earth and is considered the easier of the three open clusters to recognize, having an approximate boundary that is 24 arcminutes or about 80% the diameter of a full moon. Below is Loyd's image of open cluster M37.
Originally dicovered by Hodierna, M37 was listed by him as an object of "Nebulosae", a classsification he used to describe objects that didn't show stars to the naked eye, but which were seen when viewed through a telescope. His interest in astronomy was precocious. When he was twenty years old, he obtained the authorization to use, for his astronomical observations, the bell tower of the church of S. Nicola in Ragusa. From there he observed, between 1618 and 1619, the three comets which spurred the famous polemic that culminated in Galileo's Saggiatore. In 1622 he was ordained in Siracusa. Beginning in 1637, he served the barons of Montechiaro (who were also the Dukes of Palma) as chaplain and parish priest of the town of Palma di Montechiaro (well to the west of Ragusa near the southern shore of Sicily). They gave him an apartment on the top floor of their palace for his astronomical observations and later (1645), after endowing him with benefice, thus named him archpriest and, in 1655, court mathematician. He died in Palma di Montechiaro, April, 6th, 1660.  The Hodierna's Nebulae, A Messier's forerunner to the court of the early "Gattopardo", by Fredi De Maria

Comets

Two Tailed Comet Lulin & Exploding Comet

Loyd's Comets  Iconic Images

(n.) A celestial body, observed only in that part of its orbit that is relatively close to the sun, having a head consisting of a solid nucleus surrounded by a nebulous coma up to 2.4 million kilometers (1.5 million miles) in diameter and an elongated curved vapor tail arising from the coma when sufficiently close to the sun. Comets are thought to consist chiefly of ammonia, methane, carbon dioxide, and water.  Definitions of 'Comet' from The American Heritage® Dictionary

In late October of 2007, Comet 17P/Holmes made its usual journey through our solar system, its orbit around the Sun spanning a period of 6.9 years but with a magnitude of about 15 the comet was an impossible find without the aid of a telescope. However, over the span of just twenty-four hours that all changed as the comet gradually brightenend to become a million times more luminous and hence, visible to the naked eye. Noted Gill Ormrod of the UK's Science and Technology Facilities Council, It is not clear what caused this explosive event. One possibility is that it was hit by a meteoroid. More probably there has been a build-up of gas under part of the surface that catastrophically ruptured the surface last week. The comet, observed in 1899 and 1906, was thereafter lost for almost 60 years until seen once again in 1964 after which, it travelled along its path like any other normal comet until it brightened in 2007. Shown below is Loyd's 2007 image of Comet 17P/Holmes.On the evening of Nov. 6, 1892, amateur astronomer Edwin Holmes was scanning the night sky above his backyard in England when he spotted something no one had ever seen before: an exploding comet. One hundred and fifteen years later, Comet 17P/Holmes is exploding again.  Loyd Overcash

Loyd's Comets  Iconic Images

When we think of a comet or picture one in our mind's eye, we often see that iconic image of a bright ball wrapped in a dusty cloud, streaking through the vacum of space, a long glowing tail streaming out behind it. Indeed, these are the components that make up a comet, called the nucleus, coma, and tail. At its heart is a solid mass or core called the nucleus around which forms a fuzzy cloud called the coma and the tail, which extends away from the comet and is, like the coma, a transient feature that is present only when the comet is near the Sun. Of a comet's tail there are two types: dust and gas ion. A dust tail, which is usually yellow, contains small, solid particles that are about the same size as those found in cigarette smoke. This tail forms because sunlight acts on these small particles, gently pushing them away from the comet's nucleus. Because the pressure from sunlight is relatively weak, the dust particles end up forming a diffuse, curved tail. A gas ion tail, which is usually blue, forms when ultraviolet sunlight rips one or more electrons from gas atoms in the coma making them into ions (a process called ionization). Below are four excellent images from Loyd's skyshooter website, each one beautifully illustrating the various components that make up a comet. To enlarge an image simply hover your mouse's cursor over the picture. Clicking on an image will open it in a new window and at a slightly higher resolution. [9]

Loyd's description of his above images:
(1) Comet Hale-Bopp passing in front of the Double Cluster in Perseus. (2) Comet-Hyakutake passing in front of the handle stars of the big dipper. Taken on March 25,1996 on closest approach, only 0.1 AU or about 15 million km away. What a sight, the pale blue tail stretched over 60 deg. across the sky. (3) This shot of Comet Linear (C/2002 T7) was taken from Ft. Davis on 1-21-04. Image was taken with a Takahashi FSQ and the SBIG ST-8E. This is a 5 minute exposure. Don Pierce quotes "Those delicate streamers are tail rays, thin bundles of ionized particles and part of the ion or gas tail. This is the best image I have seen so far." (4) Comet Bradfield For those wishing to learn what comets are observable throughout the year in the northern hemisphere, check out Yoshida Seiichi`s web page COMETS FOR VIEWING in the Northern Hemisphere- a 2009 monthly calendar.

BibliographySources

Numbered Sources

Further Reading, Historical

Messier 63, Observations and DescriptionsTHE MESSIER CATALOG from SEDS. SEDS is maintained by Hartmut Frommert and Christine Kronberg and information is from one of the SEDS mirrored sites. Last Modification: March 30, 2005, accessed September 25, 2009

PROJECT: Constellation Ursa MajorAstronomical Observatory and Planetarium, Varna, Bulgaria from the ESO's Catch a Star 2002. Team Leader: Veselka Radeva, Astronomical Observatory, Varna, Bulgaria, The students are from the Astronomical courses in the Astronomical Observatory and Planetarium "N.Kopernicus" -Varna

William Herschel's catalog of Deep Sky objects A webpage from the SEDS organization. Hartmut Frommert and Christine Kronberg. This webpage was selected as Houston Astronomical Society Site Of The Week for July 1, 2004. Last Modification: January 22, 2007.

De Maria, FrediThe Hodierna's NebulaeA Messier's forerunner to the court of the early "Gattopardo" O.R.S.A. Organizzazione Ricerche e Studi di Astronomia (Organization for the Research and Study of Astronomy) Palermo (Europe). October 10, 2009.